Semi-automatic telephone system.



A. E. LUNDELL.

SEMI-AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED JUNE 24, I916.

van for: A/ben E Lunde/K by Patented Apr. 10, 1917.

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ALBEN E. LUNDELL, OF NEW YORK, 1\T Y ASSIGNOR T0 WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION 01? NEW YORK.

SEMI-AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Apr. 10, 1917.

Application filed June 24, 1916. 1 Serial No. 105,582.

To all whom it may concern:

Be it known that I, ALBEN E. LUNDELL, a citizen of the United States, residing at New York, in the county of Bronx and State of New York, have invented certain new and useful Improvements in Semi- Automatic Telephone Systems, of which the following is a full, clear, concise, and exact description.

The present invention relates to a novel circuit arrangement by which an operator in an extended trunking connection may signal a second operator, for example, a recording operator, not only initially to apprise her of the call but also after the first signal has been efi'aced by the act of the second operator in extending the call. Such signal may be employed-for different purposes but the same is especially applicable in cases Where it becomes necessary to ring a called party a second time, as, for example, where he has hungnp his receiver before the conversation was concluded.

The invention is particularly disclosed herein in a system of the semi-automatic or semi-mechanical class and in this case the operator who has the control of the sending mechanism by which the automatic switches are controlled, can come into the talking circuit at any time and as readily display the additional signal before the second operator.

The character of the invention will be more fully understood upon reference to the following detailed description taken in connection with the accompanying drawing and the scope of the invention will be particularly pointed out in the appended claims.

The drawing illustrates a circuit diagram of a system of the character referred to and which embodies the present invention.

In the particular system diagrammatically illustrated, the calling subscribers line is extended by manually connecting it to a link-circuit and the latter has its circuit extended through an automatic switch to a second link-circuit which in turn is manually connected to a third link-circuit. From this point on, the circuit may be extended in any desired way to the called subscriber. Two operators make these manualconnections respectively. Inasmuch as the'invention has to do with signaling from the first to the second operator, it is obvious that many different circuit arrangements may be employed for extending the circuit of the calling line. The system of the present diagram is merely a typical embodiment of the invention.

In this diagram, a subscribers substation M, having the usual equipment, is connected by a line L to a central oflice where the line terminates in the contacts on a jack J and is provided with the usual line relay LR, line lamp LL and cut-off relay CO. The link-circuit L extends from the plug P to the wipers of automatic switch S. A sec ond link-circuit L extends from bank contacts of the switch S to the contacts of a jack J A plug P co'riperates with the ack J to extend the call through the link-circuit L .and from this point on, as before stated, the circuit may be extended to the called line by any suitable circuits.

The operator who has control of the plug P has an operators set OS and a sender SN. The second operator, who has control of the plug P, has an operators set OS which is associated with the link-circuit L The sender is used by the operator to control the operation of the automatic switch 8. The sender may be of any approved construction. A key-board sending mechanism of the type shown in Lundell Patent No. 1,168,319, dated Jan. 18, 1916, may be employed for this purpose.

' The automatic switch S may also be of any approved type. It is here diagrammatically shown by a pair of wipers and associated bank contacts. The aforesaid Lundell patent illustrates switches which might be employed in the circuit herein disclosed.

Certain of the circuit changes are brought about by a rotary switch, termed a sequence switch. In the drawing this switch is designated SS. Thestructure of the sequence switch includes a rotatable shaft having a series'of disks of fiber or other insulating material secured thereto. On each side of each insulating disk is a circular conducting plate which is cut away or skeletonized so as to provide any desired arrangement of contacts. The plates on the opposite sides of the disk are electrically united by securing rivets. The rotatable disks are represented in the drawing in each instance by a long contact. A plurality of springs or brushes is provided for engagement with each pair of conducting disks and by means of these and by properly cutting away and arranging the plates on the insulating disk, any two or more brushes arranged for engagement therewith may be electrically united at any stage of rotation of the shaft. The positions of the sequence switch at which the various springs or brushes are in engagement with the rotatable disk, are indicated by numerals placed adjacent to the several contacts respectively.

It may be here pointed out that in tracing a circuit through the contacts of a sequence switch, the designating numeral of the wiper will be used, followed by the number of the position of the switch, the latter being in parentheses. Thus, with the switch in the seventh position and rotary contact 20 under consideration, the contact would be indicated by 2O (7 The sequence switch SS comprises rotatable contacts or wipers 20, 21, 22, 23, 24 and 25. Of these contacts all but 25 are closed in the positions indicated by the numerals adjacent to them. In the case of cont-act 25, which is shown with a projection on it scupper face, the circuit is closed at all points between the positions indicated by the numerals adjacent to it.. In

' this switch the shaft 26 which carries the wiping or movable contacts, 1s driven from a constantly rotating shaft 27 through magnetic clutch disks 28 and 29, which are brought into clutching engagement by the magnet SM.

'With this brief description of the principal portion of the diagram, we may pass on to a description of its operation when putting through a call from substation M and, in so doing, the circuit connections and other portions of the apparatus will be more fully described. If the party at substation M initiate a call by removlng his receiver from its hook, a circuit will be closed which will light line lamp LL. This circuit may be traced from the live pole of battery 30 I through the left-hand winding of relay LR,

normal contact 31 of cut-'ofi' relay GO, over i the line through the substation and back throughcontact 32 of cut-ofl-relay CO and theright-hand winding of relay LR, to

ground. The resulting energization of relay LR will light lamp LL by closing a circuit from the live pole of battery 33 through lamp LL, and closed contact 34 of relay LR, to ground. Upon observing the lighting of l'a'mp LL, the first operator, namely, the one having'control of plug P, will insert said plug into jack J and thereupon close a circuit for cut-off relay CO and control relay CR1 This circuit may be traced from the 7 live pole of battery 35' through the winding of relay CO, jack and plug contacts 36, 37,

and the winding of relay OR to ground. 'The energization of relay CO disconnects relay LR from the line and thereby deene rgiz'esit and'causes the circuit of lamp LL to be opened, with a resulting extinguishment of the signal. The energization of relay CR closes contact 38, but a circuit from battery 39 through supervisory lamp 40, closed contact 38'and normal contact 41 of supervisory relay 42, is prevented by reason of the latter relay having opened contact 41, by reason of the closing of a circuit over the subscribers line. This circuit extends from the live through repeating coil winding 44, the winding of relay 42, plug and jack sleeve contacts, one limb of line L, through the substation, back over the other limb of the line, through jack and plug tip contacts and 1;

repeating coil winding 45 to ground.

he energization of relay CR also closes contact 46 and thereby establishes a starting circuit for sequence switch SS which may be traced from the live pole of battorv S the disks 28 and 29 into clutching engagea ment and thereby rotate the various movable contacts of the switch. As soon as the switch passes outof its first position, the circuit at sequence switch contact 20 (1) is interrupted but a maintaining circuit for the magnet is established by way of contact 25 to ground, since the latter contact is closed at all positions between 1 and 7. As a result then, the sequence switch advances tothe seventh position. In so doing, it brings the operators set OS into circuit with the strands of the link-circuit L and the operator may obtain the calling partys order. The connections between the operators set and the strand of the link-circuit are made at sequence switch contact 21 (6 to 8) and 22 (6 to 8). As soon as the order is received, the first operator sets up the number on the sender SN, or otherwise manipulates it according to its construction, and through sequence contacts 49 (11) and 50 (11) transmits impulses to the mechanism of the switch S to cause it to pick out a trunk or link-circuit L to further extend the circuit of the calling line. The contacts 49 and 50 which are referred to as sequence switch contacts, are in systems of the type herein disclosed, the sequence contacts of another sequence switch, which is not shown, but for the purposes of this disclosure energized to light the lamp 56, which conpole of battery 43 stitutes the trunk signal for the second operator. The energizing circuit of trunk relay 55 extends from the live pole of battery 57 through the winding of relay 55, repeating coil winding 58, tip strand of linkcircuit L switch contacts 53, 51, tip strand of link circuit L sequence switch contacts 50 (12 to 16), 2st (6 to 8) key 59, sequence switch contact 28 (6 to 8), and repeating coil winding 60 to ground. The circuit for trunk lamp 56 extends from the live pole of battery 61 through lamp 56, closed contact 62 of cut-oft relay 63, and closed contact 6& of relay 55 to ground.

As soon as the second operator inserts plug P into jack J in response to the display of the trunk signal, the tip and sleeve strands of the link-circuit L are connected to the corresponding strands of link-circuit L and, by means of the key 65, the second operator may place her set 0S into talking relation with the first operator and receive the proper order for extending the call to the desired station. As soon as the plug 1 is inserted into J", a local circuit is closed trom the live pole of battery 66 through protective resistance 67, plug and jack contacts 68, 69, and the winding of control relay 70 to ground. The closing of this circuit energizes relay 70 and at once establishes a connection to ground from the sleeve strand of link-circuit L through the Winding of coil 71 and closed contacts 72 and 73. By the establishment of this connection, current is suitably provided for transmission purposes. It may be here pointed out that the repeating coil winding 44 is mated with a winding 7 4. Likewise repeatin coil winding 58 is mated with a winding 35 and the other windings of the latter coil are designated 76 and 77. A condenser 7 8 is interposed between windings 58 and 7 6.

When the first operator has completed. her service in establishing the connection, she may tree her set US by operating the key LO, sometimes called the listeningout key, and thereby establish a starting circuit for magnet SM of sequence switch SS through sequence contact 20 (7) and closed contact L0 to ground. This starting circuit will be followed by a maintaining circuit through sequence contact 25, which will insure an advance of the sequence switch to the eleventh position. In this position, the sequence switch contacts 21 and 22 will be open and sequence switch contact 23 (8 to 1) will. be established, thereby cutting out key 59 which is in circuit in positions 6, 7 and 8 of the sequence switch.

It may be here pointed out that when the connection to ground through contacts 72, 73 of relay 70 is established, supervisory relay 7 8 is energized to show the presence of plug P in jack J of the associated trunk or link-circuit L When both operators have performed their duties in establishing connection from substation M through the circuits L, L L and L to the desired line, they are free to take care of other calls. If, at any time subsequent to this, the second operator is to be signaled, other means than the trunk lamp 56 are employed. When the control relay 70 is energized in response to the insertion of plug P into jack J, the trunk lamp 56 is extinguished. The energization of relay 7O closes a path for current through cut-oil relay 63. This path may be traced from the live pole of battery 7 9 through the winding of relay 63, closed contacts 80, 81, and normal contact 82 to ground. The closing of this circuit at once establishes a locking circuit for relay 63 by way of contact 83-62 and closed contact 64- to ground. Contact 83 engages contact 62 so as to establish this locking circuit before the circuit of lamp 56 is broken. It will be noted that in this energized condition of relay 63, contact 82 is open.

If the called party should have hung up before the calling party had finished conversation, the latter, by operating his hook, could cause the winking of supervisory lamp 40 and thereby attract the attention of the first operator, who, by depressing her listening key L would establish a starting circuit for the magnet SM of sequence switch SS, by way of sequence contact 20 (11) and closed contact L to ground. As a result,

sequence switch SS will advance to its seventh, or listening in, position. This will enable the operator to learn from the calling party that he desires the called party to be rerung. In order to convey this information to the second operator, the first operator merely opens the contacts of key 59 which is included in the tip strand of the link-circuit L in this position of sequence switch SS, and thereby opens the circuit of trunk relay 55. The resulting opening of contact 64: provides a new path for current from battery 7 9, which extends from the live pole of battery 7 9 through the winding of relay 68, closed contacts and 81, and the winding of repeating relay 84: to ground. The latter is thereupon energized to connect battery 85 and protective resistance 86, which are in series, in bridge of the tip and sleeve strands of link-circuit L This is brought about by contacts 87 and 88 of relay 84. By placing battery 85 in bridge of the strands in this way, a trunk relay 89 is operated to display a second signal, herein shown as lamp 90. The energizing circuit for relay 89 may be traced from the live pole of battery 85 through resistance 86, closed contact 87 jack and plug tip contacts, winding of relay 89, plug and jack ring contacts, alternate contact 88 to ground. The energizing of relay 89 closes a local circuit for lamp 90 which may be traced from the live pole of battery 91 through lamp 90 and closed contact 92 of relay 89 to ground. The display of this sig nal to the second operator, who incertain instances may be the recording operator, informs her that the called-for party is to be rerung and she at once takes appropriate steps to bring about this result. As soon as the first operator has actuated key 59 to bring about this signaling of the second operator, she releases key 59 and closes key LO so as to bring her sequence switch SS out of the seventh or listening position into the eleventh position.

At the conclusion of conversation, the second operator withdraws plug P from jack J in response to any suitable supervisory indication and thereupon control relay 70 opens the branch to ground through coil 71 and causes a deenergization of supervisory relay 78, and, as a result of this changed condition, the first operator withdraws plug P from jack J and the various parts return to their normal condition in readiness for subsequent operations.

What is claimed is:

1. A telephone system comprising telephone lines, link-circuits for extending calling lines, automatic switches for connecting said link-circuits, operators sending mechanism for controlling the operation of said automatic switches, a second operators equipment associated with a link-circuit beyond said switch from the calling line, means for displaying a signal before the second operator when the calling line circuit has been extended to her position, means whereby the second operator may efface said signal, and means whereby the first operator may subsequently display a difierent signal before said second operator.

2. In a telephone system, telephone lines, a set oflink-circuits for extending the cireuits of said lines, a second set of linkcircuits,*automatic switches for connecting a link-circuit of the first set to a linkcircuit of the second set, operators sending mechanism adapted to be placed in circuit with link-circuits of said first set to control the operation of said switches, a second operators equipment available for connection to the link-circuits of said second set, means responsive to the operation of said switch to display a signal before said second operator, means under the second operators control for efiacing said signal, and means under the first operators control for displaying a further signal before said second operator whenever said first signal is effaced. V

3. In a telephone system, telephone lines,

link-circuits for uniting said lines into conversational circuits, automatic switches for use in establishing such circuits,an operators equipment associated with said link-circuits at one point, a second operators equipment associated with said link-circuits at another point, two signals before said second operator, means for displaying one of said signals in response to the operation of an automatic switch, means under the control of the second operator for efi'acing said one signal, and means subsequently under the control of the first operator for displaying said other signal.

4. In a telephone system, trunk lines, automatic switch mechanism for connecting corresponding strands of trunks to extend a circuit, a trunk relay, a battery and connections whereby said relay is energized over said extended trunk circuit, a signal displayed in response to the energization of said relay, a cut-oil relay for eflacing said signal, means for locking up said cut-oil relay through contacts of said trunk relay, a repeating relay, a second trunk relay, :1 second signal operated by said second trunk relay, battery and connections for actuating said second trunk relay over another portion of the extended trunk circuit to display said second signal in response to the energization of said repeating relay, and circuit connections whereby said repeating relay is energized in response to a deenergization of said first trunk relay.

5. In a telephone system, a trunk, a trunk relay connected thereto, means for energizing said relay over said trunk, a trunk signal displayed in response to the energization of said trunk relay, a cut-off relay having a locking connection through contacts of said trunk relay, a plug and a jack for connecting to said trunk, a control relay in circuit with a ring of said ack, battery connections to the mating contact of said plug whereby said control relay is energized upon the connection of said plug and jack, a repeating relay, a path for current through said cut-off and repeating relays through contacts of said control relay, battery and connections adapted to be connected to said jack tip and sleeve contacts by said repeating relay, a second trunk relay in bridge of the tip and sleeve contacts of said plug whereby the latter relay is energized in response to the energization of the former, and a second signal displayed in response to the energization of said second trunk relay.

In witness whereof, I h'ereunto subscribe my name this 23rd day of June, A. D. 1916.

ALBEN E. LUNDELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,- Washington, D. C. I 

